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We investigate structure of self-gravitating disks, their fragmentation and evolution of the fragments (the clumps) using both analytic approach and three-dimensional radiation hydrodynamics simulations starting from molecular cores. The simulations show that non-local radiative transfer determines disk temperature. We find the disk structure is well described by an analytical model of quasi-steady self-gravitating disk with radial radiative transfer. Because the radiative process is not local and radiation from the interstellar medium cannot be ignored, the local radiative cooling would not be balanced with the viscous heating in a massive disk around a low mass star. In our simulations, there are cases in which the disk does not fragment even though it satisfies the fragmentation criterion based on disk cooling time ($Q sim 1$ and $Omega t_{rm cool}sim 1$). This indicates that at least the criterion is not sufficient condition for fragmentation. We determine the parameter range for the host cloud core in which disk fragmentation occurs. In addition, we show that the temperature evolution of the center of the clump is close to that of typical first cores and the minimum initial mass of clumps to be about a few Jupiter mass.
It is quite likely that self-gravity will play an important role in the evolution of accretion discs, in particular those around young stars, and those around supermassive black holes. We summarise, here, our current understanding of the evolution of
We present new sub-arcsecond (0.7) Combined Array for Research in Millimeter-wave Astronomy (CARMA) observations of the 1.3 mm continuum emission from circumstellar disks around 11 low and intermediate mass pre-main sequence stars. High resolution ob
Using numerical hydrodynamics simulations we studied the gravitational collapse of pre-stellar cores of sub-solar mass embedded into a low-density external environment. Four models with different magnitude and direction of rotation of the external en
The long-term evolution of a circumstellar disk starting from its formation and ending in the T Tauri phase was simulated numerically with the purpose of studying the evolution of dust in the disk with distinct values of viscous alpha-parameter and d
We present a mechanism for the crystalline silicate production associated with the formation and subsequent destruction of massive fragments in young protostellar disks. The fragments form in the embedded phase of star formation via disk fragmentatio